Scheduling design processes with interdependent tasks: A systems analysis approach

This research develops a model to determine the optimal task schedule for a product development process. The model takes into account both the speed of the design process and the quality of the system it produces. In particular, the model also accounts for interdependencies in the design process and for the effects of concurrent engineering. Parallel development speeds up the process, but requires increased communication among tasks. If the communication fails to occur, errors and inconsistencies can develop in the product, leading to a lower system reliability. For any process, there needs to be a balance between speed of design completion and product quality. This research develops a series of analytical models and a simulation to capture the effects of schedule changes and interdependence between design tasks. The models provide as output the expected time of project completion and the expected number of design errors present in each design component or subsystem. The full distribution for these quantities is calculated in the simulation. The conditions for convergence are also derived for each model. The models are illustrated through the development of the spacecraft control electronics (SCE) for a new communications satellite.